Yeah, you'll likely only get half an R-value with that thin of pad. There have been some studies by the US Military (via Richard N) and humans seem to be really only notice a difference in temp between roughly .5 R. That is to say that you may or may not feel a difference and if you do it will be slight. Our bodies really just register a few types of temperatures. On the lower side that's roughly:Cool, Cold, Bitter, and "There isn't a word because even the Eskimo's teeth are chattering too much to speak"

The numbers are great but our bodies just aren't that finely tuned to measure temperature =/

Thanks folks. Not too encouraging but better than no pad beneath the ProLite. Perhaps I'll use the flooring foam pad with my Ridgerest instead of the ProLite.

Backyard testing shall commence. The sub freezing weather has arrived in the 'Vegas Valley. First I'll test on my cement patio and then on the grass W/ plastic ground cloth for both tests. The cement patio should be the best test due to better condictivity of heat into the cement.

As soon as I get my new Scarp 2 this week I may head to 9,000 ft. in the nearby Spring Mountains to test successful mattress combos in weather in the teens. I'll keep you posted as to the results.